Define the movements of the back and its skeletal elements.
Define the normal and basic pathological spinal (postural) curvatures.
Describe a typical vertebra and the characteristics of vertebrae from different regions of the vertebral column.
Understand how the intervertebral joints contribute to movements of the vertebral column.
Describe the ligaments of the vertebral column. Describe the intervertebral disc and the joint in which it is found. Understand the meaning of a "herniated disc."
Understand how spinal nerves emerge from the vertebral column.
Describe the craniovertebral joints.
Define and differentiate between the extrinsic and intrinsic muscle groups associated with the back.
Study the attachments and functions of the extrinsic back muscles (these muscles will also be considered with the upper extremity)
Trapezius
Lattissimus dorsi
Levator scapulae
Rhomboids
Serratus posterior
Study the attachments and functions of the intrinsic back muscles.
Splenius capitis and cervicis
Erector spinae
Semispinalis cervicis and thoracis
Study the blood supply of the spinal cord and the vertebral column.
Lecture Notes
Introduction
"study early and often" - do not fall behind
"I do not write trick questions"
Bring clickers to class - questions from previous lecture asked in the beginning of class
Movements of the Back (4 different movements)
Flexion - bending forward
Extension - bending backwards
Lateral Flexion - bending sideways
Rotation - rotating the back
Vertebral Column (31-33 vertebrae)
The staff will use numbers to denote vertebrae (T12 instead of TXII)
7 cervical
12 thoracic
5 lumbar
5 sacral (usually fused)
2-4 coccygeal (typically fused as well)
Vertebrae Prominence - C7 (first vertebrae you can feel on your neck)
Sacral hiatus - located posteriorly is an important landmark
contains fat and the filum terminale
enclosed by a membrane
important for caudal anesthesia (epidural)
Curvature of the Back
Development
primary curvature is concave as a fetus
first secondary curvature occurs in the lumbar region after birth due to weight bearing
second secondary curvature occurs in the cervical region around age 4
vertebral arch = laminae (lamina is "flat") + pedicles (pedicle is "little foot")
vertebral foramen = posterior aspect of the vertebral body + vertebral arch
multiple vertebral foramina = vertebral canal (holds the spinal cord)
articular processes (articular = "joint")
inferior articular facet (facet = "smooth face")
superior articular facet
intervertebral foramen = superior vertebral notch + inferior vertebral notch (this is where the spinal nerves emerge from the vertebral column, the DRG are in the vertebral canal close to the foramen)
Regional Characteristics of Vertebrae
Distinguishing features
Body
Processes
Foramina
Zygapophysial Joints (Z-joint) - joints between vertebrae
Cervical
DIAGNOSTIC: transverse process has a hole in it (transverse foramen) which allows the vertebral artery to pass through
some vertebrae have a bifid (2-prong) spinous process which tends to be shorter and angled slightly down
the body tends to be small and squarish
Z-joint facing superiorly and inferiorly to facilitate rotation
Thoracic
DIAGNOSTIC: facets on the body (articulate with the head of the rib) and the transverse process (articulate wit the tubercle of the rib). Also note that a rib articulates with facets on the bodies of adjacent vertebrae.
the body is heart shaped
spinous processes tend to be long and angled sharply downward
Z-joint anterior and posterior, least mobile region of the vertebral column
Lumbar
DIAGNOSTIC: process of elimination! (not cervical or thoracic)
very large body, kidney shaped
transverse process are large and lateral
spinous process are short and stocky
Z-joint in the sagittal plane to facilitate flexion and extension
Atlas (C1) and Axis (C2)
Atlas (C1)
As Atlas was a titan that held up the world, the Atlas vertebrae holds up the skull
does not really have a spinous process, instead has a posterior tubercle (tubercles are bumps on bones which tend to attach to muscles or ligaments)
does not have a vertebral body, has anterior and posterior arches instead
Axis (C2)
the remnant of the C1 body is fused to C2: odontoid process/dens
otherwise has the typical characteristics of other cervical vertebrae (bifid spinous process, transverse foramen, etc)
Vertebral Ligaments
Longitudinal ligaments run on both sides of the vertebral body
anterior longitudinal ligament is wider than the posterior
posterior longitudinal ligament forms the anterior wall of the vertebral column, supports dorsal and ventral roots
Interspinous ligament fills in the space between the spinous processes
Supraspinous ligament articulates with the tip of the spinous processes
Ligamentum flavum connects adjacent laminae and has a yellowish hue (flavum = "yellow")
in the cervical region, the supraspinous ligament is replaced by the ligamentum nuchae which serves as the attachment point for neck muscles. This is also the reason why you cannot palpate C1-C6
Intervertebral Discs
Anulus fibrosus - rings of fibrocartilage (anuli = "rings")
thinner posteriorly
vascularized (has blood supply)
Nucleus pulposus - mostly mucoid (70-90% water with reticular and collagen fibers)
25% of adult height is due to the intervertebral discs
as a person ages, the water content decreases making it thinner and more easy to rupture
this is why a person gets shorter as they age
Avascular
Nomenclature
L4-5 disc = intervertebral disc between L4 and L5 (do not use the old system of nomenclature)
There is no C1-2 disc because the C1 body is fused to the C2 vertebrae
Herniation
most commonly herniates in the posterior and lateral direction in cervical and lumbar regions
thoracic herniation is rare
A herniation in L4-5 disc will affect the lower nerve root (L5) as the L4 nerve root will leave just below the pedicle and above the herniation. It also will not affect lower nerve roots (S1, etc) as they are able to move out of the way
A herniation in the C7-T1 disc will affect the C8 nerve root leaving the area
Pain of herniation is from inflammation of nerve covering as it rubs against rupture
Atlanto-occipital Joint
Origin = typically proximal and the stable part of the joint
Insertion = typically distal and the movable part of the joint
The atlantooccipital membrane fills the space between C1 and the occipital bone
in the upper cervical region (C2 and up), the posterior longitudinal ligament becomes the tectorial membrane
the cruciform ligament (cruciform = "cross-shaped") covers the dens
the transverse ligament holds the dens on the anterior arch of the atlas
alar ligaments (ala = "wing") attaches the dens to the occipital bone
apical ligament holds the dens to the occipital bone superiorly
when the dens snaps (hanging, trauma), the spinal cord is severed
Muscles of the Vertebral Column
You should know the following (in order of importance)
function
innervation
origins and insertions
Suboccipital and transversospinal (deep intrinsic back muscle) are not covered in this course
Extrinsic back muscles are also extrinsic muscles of the shoulder and will be covered in the shoulder lecture tomorrow
innervated by the ventral rami
connect the upper limb to the trunk and control movement of the upper limb
Intrinsic Back Muscles
innervated by the dorsal rami
maintain posture and control movement of the vertebral column and head
Superficial Layer (splenius muscles)
Splenius capitis (splenius = "bandage")
origin: spinous processes (SP) of the lower cervical/upper thoracic vertebrae
insertion: cranium
function: extend head (bilateral), lateral flex, rotate face (unilateral)
Splenius cervicis
Origin: SP of thoracic vertebrae
insertion: transverse processes (TVP) of cervical vertebrae
insertion: spinous processes and transverse processes of the cervical and thoracic vertebrae, cranium
function: extend head and vertebral column
Deep Layer (semispinalis muscles)
Semispinalis Capitis
know that it is a deep muscle
will be asked to ID in lab
origin: transverse processes of the lower cervical and upper thoracic
insertion: cranium
function: extend head
Multifidus
spans 2 vertebral levels
important core muscles
erector spinae muscles counteract gravity and keeps you erect
Innervation of the Back
the medial branch goes through the muscles to the skin surface to form cutaneous nerves
angles of the ribs are the edges of the back dermatomes
Vasculature of the Back
Regional "feeder" Arteries
Segmental Spinal Arteries
Radicular arteries
do not supply the spinal cord because they do not meet the three major longitudinal arteries
supplies the anterior/posterior, DRG, dorsal roots, and ventral roots
Segmental medullary arteries
they do supply the spinal cord
Ligation of the great segmental medullary artery of Ademkiewicz (accidently cut during surgery) will cause paraplegia because it supplies the lower 2/3 of the spinal cord
Cervical Region
Vertebral a.
Ascending Cervical a.
Deep Cervical a.
Thoracic Region
Posterior Intercostal a.
Abdominal Region
Lumbar aa.
Pelvic Region
Lateral Sacral a.
Major longitudinal arteries
Anterior spinal artery
2 Posterior spinal arteries
supply the spinal cord
Venous Drainage
Internal venous plexus (epidural) is inside the vertebral canal and drains into the external venous plexus
External venous plexus is outside the vertebral column
Table of Contents
Back
Dr. Hankin
5 Nov 2007 @ 9 AM
Objectives
Lecture Notes
Introduction
"study early and often" - do not fall behind"I do not write trick questions"
Bring clickers to class - questions from previous lecture asked in the beginning of class
Movements of the Back (4 different movements)
Vertebral Column (31-33 vertebrae)
Curvature of the Back
Typical Vertebra
Regional Characteristics of Vertebrae
Atlas (C1) and Axis (C2)
Vertebral Ligaments
Intervertebral Discs
Atlanto-occipital Joint
Muscles of the Vertebral Column
Intrinsic Back Muscles
Innervation of the Back
Vasculature of the Back